Water-soluble textile resin finish



United States Patent 3,211,805 WATER-SOLUBLE TEXTILE RESIN FINISHWilliam F. Herbes, Bridgewater Township, Somerset County, and RaymondPolansky, Middlesex, N.J., as-

siguors to American Cyanamid Company, New York,

N .Y., a corporation of Maine N0 Drawing. Filed May 17, 1961, Ser. No.110,622

5 Claims. (Cl. 260'849) This application is a continuation-in-part ofour copending application Serial No. 732,815, filed May 5, 1958, and nowabandoned.

The present invention relates to a Water-soluble textile resin finish,the process for preparing the same and to the process for finishingtextile materials therewith. More particularly, the present inventionrelates to a novel method for preparing water-solublemelamine-formaldehyde-ethylene urea-formaldehyde resinous mixtures, themixtures themselves, and the process for treating textiles therewith.

Alkylated methylol melamine resins, and more particularly water-solublemethylated methylol melamine resins, have been prepared heretofore. Manyof the prior art procedures, such as those described in US. Patent No.2,529,856, have disclosed the preparation of methylated methylolmelamines in more or less specific terms, and have described methods forthe preparation of such products having varying degrees of substitutionranging from monomethyl monomethylol melamine to hexamethyl hexamethylolmelamine.

Frequently, prior art references refer to the reaction products soprepared as being highly stable and infinitely soluble in water. Inpractice, it has been found that by adhering to the conditions describedin such disclosures, many infinitely water-soluble melamine resins canbe so prepared, as for example, trimethyl trimethylol melamine,tetramethyl pentamethylol melamine and the like. However, it has beenour experience that when these teachings were applied to the preparationof a substantially fully alkylated, substantially fully methylolatedmelamine, the resulting product did not possess the necessary degree ofwater solubility and stability for a good textile resin.

For many of the uses of such reaction products as, for example, in thefield of surface coatings, laminating resins and the like, the qualitiesof water solubility and stability are not important. This is due to thefact that in most instances the melamine resins employed in thepreparation of such compositions are cut or employed in organic solventmediums, as for example, xylene, benzene and the like.

The reasons for the poor water solubility and stability characteristicsof these substantially fully alkylated, substantially fully methylolatedmelamine resins of the prior art have been speculated upon a number ofoccasions. A strong body of opinion supports the theory that thesedeficiencies are developed in the product when it is attempted to obtainfull alkylation because of the conditions employed during alkylation.

Melamine-formaldehyde resins having varying degrees of substitution,both as methylolated products and as alkylated methylol melamineresinous materials have been widely disclosed and widely employed forpurposes of finishing textile materials. The use of such resins oncellulosic textile fabric have a number of important advantages. Thus,for example, they impart excellent shrinkage control and wrinkleresistance to textile materials and particularly cellulosic textilematerials and have excellent durability. Still further, such textilematerials treated with melamine-formaldehyde textile finishing resins donot suffer from marked deficiencies in tensile 3,211,805 Patented Get.12, 1965 strength when scorched, subsequent to chlorine bleaching. Adisadvantage of the melamine-formaldehyde condensate textile finishingresins is, however, that when employed on white goods which arerepeatedly subjected to chlorine bleaching, that after a substantialnumber of washes, the textile fabric begins to yell-ow as a result ofchlorine retention.

In order to avoid the disadvantages of yellowing following chlorinebleaching, which resulted when methylated methylol melamine resins wereused, recourse was had to the use of ethylene urea type resins. Thisproduct had the advantage that it did not discolor white cellulosicfabric treated therewith after bleaching with chlorine and further thatit could be used at high concentrations to obtain excellent wrinkleresistance without imparting stiffness, particularly on rayon fabric.The ethylene urea type resin, however, had the disadvantage that it gavea substantially greater loss in tensile strength than melamine resinswhen a fabric treated therewith was subjected to scorching afterchlorine bleaching.

Several attempts have been made heretofore in the prior art to produceformulations of both the melamineformaldehyde condensate type resin andthe ethylene urea-formaldehyde type resin to provide compositions which,when applied to cellulosic textile fabrics, minimized the deficienciesof these individual resinous materials. As witness to prior art effortsin this area, US. Patents Nos. 2,690,404 and 2,804,402 may be noted. Ineach of these references, mixtures or blends of polymethylol melaminesand dimethylol ethylene urea are prepared with the components beingpresent in critical proportions.

These mixtures as described in the above referred to US. patents are notwithout limitation. Thus, for example, even within the optimumconditions defined by these references, fabrics treated therewith aresubject to yellowing due to chlorine retention upon repeated andextended washing due to the melamine component and the tensile strengthlikewise suffers when finished fabric so treated is scorched afterrepeated and extended washing in the presence of chlorine bleach due tothe presence of the ethylene urea-formaldehyde condensate component ofthe resinous mixture.

The effect of this continuing to yellow after repeated and extendedlaundering in the presence of chlorine is in part the result of thenature of the melamine-formaldehyde component used in these compositionsor condensates. Thus, for example, the references illustrate such knownmethylated methylol melamine condensates as the trimethyl trimethylolmelamine and the pentamethyl pentamethylol melamine. While the yellowingmay be diminished by increasing the ethylene urea content of theformulation, the presence of increased amounts of ethylene urea resultsin an undesirable increase in tensile strength loss of the fabric, whenthe latter is scorched following chlorine bleaching.

Accordingly, it is an object of the present invention to provide aprocess 'for preparing a substantially fully etherified, substantiallyfully methylolated melamine-ethylene urea-formaldehyde resinouscomposition characterized by infinite solubility in water and excellentstability.

It is a further object of the present invention to provide such acomposition which, when applied to cellulose containing textilematerials results in a material which is substantially free fromdiscoloration due to chlorine retention, even though the melaminecomponent is present in a substantial amount, and which is characterizedby good tensile strength when scorched after chlorine bleaching, eventhough the ethylene urea component is present in a substantial amount.

Another object of the present invention is to provide a process for thefinishing of textile materials, and in particular cellulose-containingtextile materials, with such a resinous composition whereby goodshrinkage control and wrinkle resistance are obtained with minimumdeleterious effects of discoloration and loss of tensile strength of thetreated fabric clue to chlorine retention.

A still further object of the present invention is to provide a textilefabric containing cellulosic materials finished with the novel resins ofthis invention.

These and other objects and advantages of the present invention willbecome more apparent from the detailed description set forthhereinbelow.

In accordance with one aspect of the present invention, a process isprovided for preparing a water-soluble, substantially fully etherified,substantially fully methylolated melamine, ethylene urea-formaldehydetextile finishing composition. This process comprises preparing asubstantially fully methylolated melamine by reacting relative moleratios of -1 mole of melamine and an excess of formaldehyde representedby an amount between about 8 and 20 moles of formaldehyde asparaformaldehyde at a temperature between 30 and 80 C. at a pH between 7and 11 in the presence of at least 6 moles of methanol until the clearsolution is formed and the reaction is complete, as determined by theamount of free formaldehyde present. Thereafter, sufficient additionalmethanol is added to the reaction mixture to make a total of at leastmoles of methanol therein, after which the pH of said mixture isadjusted to a value of below 4 and said mixture is stirred whilemaintaining a temperature between 15 and 60 C. until a complete solutionis obtained.

Thereafter, the pH of the reaction mixture is adjusted to a valuebetween about 8 and 10 and the mixture vacuum concentrated to a desiredsolids content, said vacuum concentration being for purposes of removingexcess formaldehyde and methanol. Ethylene urea in an amount up to about1.2 moles is added and reacted with the excess formaldehyde at atemperature of between and 80 C. until reaction is complete.

In a copending application, Serial No. 732,814, filed May 5, 1958, animproved substantially fully etherified, substantially fullymethylolated melamine resin is described. Such materials may be preparedby at least two general methods, each of which has certain shortcomings.Thus, a two-kettle process may be employed in which a substantiallyfully methylolated melamine is isolated. Such a process results in theeliminating of substantial amounts of excess formaldehyde andetherification is carried out in 'a second operation, using the isolatedintermediate. In 'a second procedure, a one-kettle process, asubstantially fully methylolated melamine is not isolated before the.etherification step, and consequently the product contains considerableamounts of free formaldehyde. A twokettle process has the advantage ofgiving a product containing essentially no free formaldehyde, but such aprocess is more expensive than that of the second. The onekettleprocess, although less expensive, results in a product containingundesirably large amounts of free formaldehyde. Said amount of freeformaldehyde is sufficient to render the resin unattractive commerciallybecause of obnoxious odors which are produced. In efforts to reduce thefree formaldehyde to an acceptable level of, say, less than 3%, based ontotal composition as by vacuum concentration, the solubility in water ofthe resin is impaired.

The substantially fully etherified, substantially fully methylolatedmelamines prepared in accordance with the procedures described above inthe above referred to copending application may be employed in preparingthe resinous finishing compositions of this invention by mechanicallyblending this product with the hereinafter described amounts of ethyleneurea-formaldehyde condensate, but such blending is objectionableprocesswise, as costs are increased or the product is unsatisfactory dueto the presence of excess formaldehyde. Thus, in accordi ance with thepresent invention, the novel finishing compositions are preferablyprepared, in general, in accordance with the one-kettle processdescribed in the aboveidentified copending application. By employingthis procedure, these shortcomings are readily overcome.

The composition of this invention may be characterized as a mixturecomprising on a relative mole basis 1 mole of a substantially fullyetherified, substantially fully methylolated melamine and from betweenabout 0.6 and about 1.2 moles of an ethylene urea-formaldehydecondensate, preferably dimethylol ethylene urea. Preferably, the moleratios on a relative basis are 1 mole of the melamine component andbetween 0.8 and 1.0 mole of the ethylene urea component.

The product of this invention is preferably characterized as a reactionmixture, referring to the product prepared by the addition of ethyleneurea to the melamine condensate, whereby free formaldehyde presentreacts with the ethylene urea to form the methylol condensate.

The resinous composition of this invention is further characterized byinfinite solubility in water and excellent stability characteristics,even though the melamine component is a substantially fully etherified,substantially fully methylolated product, and is always present in themixture in substantial amounts.

More specifically in accordance with the present invention, melamine andparaformaldehyde are reacted in relative mole ratios of from 1 to about8 to 1 to 20 and preferably in mole ratios of 1 to 8 to 1 to 12,respectively. In these mole ratios, the paraformaldehyde is expressed asmonomeric formaldehyde. These reactants are heated in a suitablereaction vessel in the presence of methanol at a pH of between 7 and 11,and preferably between 8 and 10 at a temperature of between 30 and C.,and preferably between 60 and 80 C. until the reaction is complete asevidenced by free formaldehyde determination.

The amount of methanol added during the methylolation of the melamineshould be at least 6 moles and preferably at least 8 moles of alcoholper mole of melamine in the reaction mixture. It is esesntial that atleast 6 moles of alcohol be added in order to achieve a stirrablereaction mixture.

After methylolation is complete, the substantially fully methylolatedmelamine is etherified. This is accomplished by the addition ofsufficient methanol to make a total of between 10 and 20 moles andpreferably between 12 and 18 moles per mole of melamine. As will appearmore clearly hereinafter, it is sometimes desirable duringetherification to add certain monoalkyl ethers of diethylene glycol andethylene glycol in an amount of at least 0.1

mole and preferably between about 0.25 and 1 mole per mole of melamine,though up to 2.5 moles may be employed.

Thereafter, the pH of the reaction mixture is adjusted to a value ofbelow 4 with a suitable acid and preferably to a value below 3.5, andthe mixture is stirred at a temperature of between 15 and 60 C. andpreferably between 30 and 50 C., until complete solution is obtained.Usually, about one hours time is required for alkylation. Thereafter,the pH of the reaction mixture is adjusted to between 8 and 10 with analkaline material such as caustic soda, potassium hydroxide, sodiumcarbonate, sodium bicarbonate and the like, and the solution isconcentrated in vacuo. The remaining syrup contains free formaldehyde,the amount depending upon the quantity of paraformaldehyde used in themethylolation step, and the extent of vacuum concentration, whereby aportion of the free formaldehyde is removed from the reaction mixture.

After vacuum concentration sufiicient ethylene urea is added to thereaction mixture of the etherified, methylolated melamine to combinewith a major portion of the free formaldehyde and to give the dimethylolethylene urea. Preferably, not over 1.0 moles of ethylene urea per moleof melamine should be employed, though amounts up to about 1.2 moles ofethylene urea per mole of melamine have been employed with satisfactoryresults. At this stage, it may be desirable to add sufiicient water withthe ethylene urea to achieve a desired solids content in the finalproduct.

After the addition of the ethylene urea, the reaction mixture is stirredat a temperature between 30 and 80 C. and preferably at a temperaturebetween 50 and 70 C. until the reaction between the ethylene urea andformaldehyde is completed, as determined by free formaldehydedetermination. Thereafter, the pH of the reaction mixture is adjusted toa value of between 7 and 9 with any suitable alkaline material, and thesolution is cooled and filtered, as for example at a temperature ofbetween about 30 and 40 C.

It will be seen that the above-defined process is basically oressentially a one-pot process in which the methylolation stage iscarried out in the presence of an alcohol, preferably methanol, whileemploying paraformaldehyde. By employing these components and under theabove conditions, it becomes unnecessary to isolate the substantiallyfully methylolated melamine before the etherification step, in view ofthe comparatively small amount of water in the reaction medium. Itshould be noted that the upper limit on the amount of alcohol employedin the reaction medium during methylolation is not critical, and that ifdesired the total alcohol charge may be charged initially, as opposed tothe double charge described above, and illustrated in more detailhereinbelow, though the latter is preferred.

As indicated herein-above, the etherification may be carried out withmethanol alone or in conjunction with certain monoalkyl ethers ofdiethylene glycol and ethylene glycol. Although highly satisfactoryproducts are obtained employing methanol alone, the use of relativelysmall amounts of one of the above-identified ethers, which have boilingpoints higher than that of methanol, results in a process advantage inthat it facilitates the concentration of the final productsubstantially. Employing the ether, the alcohol is completely removedand more importantly the free formaldehyde content is reduced to a pointwhere the recommended amount of ethylene urea will be sufficient forcombining with substantially all of the remaining free formaldehyde.

Although methanol or methyl alcohol is the definitely preferred alcohol,employed in the present process, it is believed that other saturatedaliphatic alcohols containing from 2 to 4 carbon atoms, such as ethanol,the propyl alcohols, the butyl alcohols or mixtures of these, may beemployed with some measure of success.

The monoalkyl ethers of diethylene glycol which may be employed containfrom 1 to 4 carbon atoms in the alkyl group. Thus, for example, methyl,ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl and tertiarybutyl ethers of diethylene glycol may be employed, as well as mixturesof said ethers. Of these ethers, the ethyl ether of diethylene glycol ispreferred. The monoalkyl ethers of ethylene glycol employable includethose wherein the alkyl group contains 1 to 3 carbon atoms or mixturesthereof as represented by methyl, ethyl, propyl, isopropyl and ethyleneglycol.

Preparatory to the etherification of the substantially fullymethylolated melamine, the pH of the reaction mixture is adjusted to apH value below 4 and preferably below 3.5. This may be accomplished byemploying any of a number of suitable acidic catalysts, as for examplesulfuric, hydrochloric, nitric, phosphoric, oxalic and toluene sulfonicacids. Nitric acid is preferred, partic ularly when sodium hydroxide isemployed as the alkaline catalyst during methylolation, for reasons thatwill appear more clearly hereinafter.

The amount of acid employed not only determines the pH of the reactionmixture, but also largely influences 6 the time required to achievecomplete etherification. In general, longer reaction times are requiredwhen minimum amounts of acid are employed and conversely shorterreaction periods are required when maximum amounts of acid catalysts areemployed.

As indicated hereinabove, the amount of acid catalyst added is an amountsufficient to adjust the pH to a value below 4 and preferably below 3.5.Defined on a mole basis, per mole of melamine, the amount of acidemployed should be from between about 0.05 and 0.30 per mole of melamineand preferably from between 0.08 and 0.16 per mole of melamine.

The substantially fully etherified and substantially fully methylolatedmelamine is preferably vacuum concentrated in order to remove excessmethanol and some of the free formaldehyde, preferably by employingknown vacuum concentration techniques. Experience has shown that thefinal internal temperature of the melamine reaction product should beabout C. employing a vacuum of from 25 to 26 inches of mercury.

The expression 25 to 26" of mercury and similar ex pressions as they areused herein, refer to commercial dial gauge readings. In principle,these readings are ob tained as follows. A hollow tube is connected froman opening in the container, the vacuum in which it is to be measured,to the upper end of a vertical glass tube, the lower end of which is ina pool of mercury. As a vacuum pump exhausts the air from the containerand the glass tube, atmospheric pressure forces mercury up the saidtube. The height to which the mercury rises is the measure of the vacuumin the container, which in the present instance has been read in inches.

When an ether of a suitable glycol is not employed, the vacuumconcentration is more difficult, since the presence of the ether servesto make the reaction mixture more fluid at 7080 C. when most of themethanol has been removed. However, the concentration can beaccomplished without using the ether and with a final internaltemperature of about 80 C. Under these conditions, the concentratedproduct has a viscosity of 5000- 6000 centipoises at 25 C., whereas withthe ethyl ether the viscosity was 800-1400 centipoises at 25 C. Aspreviously stated, the termination of the vacuum concentration at atemperature lower than 80 C. produces a concentrate containing more freeformaldehyde. The presence of increased amounts of formaldehyde in theconcentrate is undesirable, since this would require increased usage ofethylene urea to reduce the formaldehyde content to an acceptable level,say less than 3%, based on the total product weight, and thus thetensile strength of the resulting finished textile material would beadversely affected.

Although it is recommended that approximately 1.0 mole of ethylene ureaper mole of melamine resin be used, experimental evidence indicates thatusage as high as about 1.2 moles of ethylene urea are also satisfactory.However, it is known that dimethylol ethylene urea causes a greaterstrength loss due to chlorine retention than the fully etherified, fullymethylolated melamine. In the above referred to US. patents, namely,2,690,404 and 2,804,402, it is essential that the resin mixture containmore moles of ethylene urea than melamine in order to minimizediscoloration due to chlorine retention. Employing the substantiallyfully etherified, substantially fully methylolated resin of the presentinvention, which of itself results in substantially no discoloration dueto chlorine retention when compared with other knownmelamineformaldehyde condensates, it will be apparent that the principalshortcoming resides in the loss of tensile strength due to chlorineretention as a result of the ethylene ureaformaldehyde component beingpresent in the mixture.

In accordance with the present process, the substantially fullyetherified, substantially fully methylolated melamine is concentrated inorder to reduce excess free formaldehyde and methanol. Thisconcentration is never such as will adversely affect the solubility ofthe product, nor reduce the free formaldehyde content to an extent suchthat the ethylene urea added cannot be fully converted to dimethylolethylene urea. In this connection, at the time of the addition ofethylene urea, the concentrated melamine reaction product may contain ashigh as about 15% free formaldehyde based on the weight of the totalreaction mixture, though preferably much less, but an amount sufficientto fully methylolate the ethylene urea. After the methylolation of theethylene urea, the reaction mixture normally will contain from traces offormaldehyde to a maximum of about 2%, based on the weight of the totalreaction mixture.

By the expression substantially fully methylolated melamine as it isused herein, it is meant a product which contains a minimum of 5.8 molesof combined formaldehyde per mole of melamine and preferably up to 6combined moles of formaldehyde per mole of melamine.

By the expression substantially fully etherified as it is employedherein, it is meant that at least 5.6 of the available methylol groupson the melamine have been reacted, with methanol, and if employed, theselected monoalkyl ethers of diethylene glycol and ethylene glycol. Inthis connection, the etherifying groups are methyl or principallymethyl, with one mole of the melamine condensate containing up to 2.5moles of alkoxyethoxyethyl and/or alkoxyethyl groups, and preferablyfrom between about 0.25 and about 1 mole of such groups, the remainingetherifying group being methyl.

By the expression excellent stability and similar expressions as theyare employed herein, it is meant stability in aqueous solution in allconcentrations for at least 12 weeks at 12 and 37 C.

By the expression infinite solubility as it and similar expressions areemployed herein, it is meant that the present resin composition isreadily and easily soluble and dilutable in water in all proportions andthat solutions containing the resin in all proportions remain clear.

The resin composition of this invention is applied to textile materialsand preferably textile materials containing at least 50% cellulose, inorder to impart shrinkage control and a high degree of wrinkleresistance thereto, without discoloration due to chlorine retention fromre-' peated chlorine-containing washings and minimum loss of tensilestrength also due to chlorine retention.

By the term cellulosic material as that term is employed herein, it ismeant fibers, yarns, filaments, formed fabric, whether woven ornon-woven, felted or otherwise formed, containing at least 50% ofcellulose fiber prepared from cotton, rayon, linen, flax and othercellulosic materials. These cellulosic textile materials may be employedin combination with other non-cellulosic materials, as for example, theymay be blended with other natural or synthetic fibers, as for example,wool, nylon, acrylic and polyester fibers, and the like.

The resins of this invention may be applied to textile materials,preferably a formed cellulosic containing fabric, with a suitable curingcatalyst. The resinous composition and catalyst may be applied by anyconventional technique, such as immersion, padding, spraying and thelike and followed, where necessary, by squeezing, hydroextraction orsimilar processes, in order to affix the desired amount of resin solidsonto the fabric.

The method of application should be such that from about 1 to about 25%,and in some instances higher amounts of the resinous product of thisinvention, based on the weight of the fabric, are deposited thereon.Within certain limits, the amount of resin applied depends upon theparticular type of fabric being treated. Thus, when treating fabricconsisting of fibrous cellulosic materials, the concentration of theorder of from about 1 to 25% and more, particularly from 3 to resinsolids, based on the dry weight of the fabric, may be employed.

The catalyst utilized may be free acid, acid salts, alkanolamine saltsand the like. The concentration of catalyst employed may range fromabout 0.1 to about or higher, based on the weight of the resin solids,depending upon the particular catalyst type employed. Thus, for example,from between about 0.1 and about 10% of a free acid, such as phosphoric,tartaric, oxalic or the like, may be employed, while in the case ofammonium chloride amounts of from between 0.5 and about 10% are used. Inthe case of amine salts, including alkanolamine salts, such asdiethanolamine hydrochloride, from about 1.0 to about 10% are mostuseful, while with respect to salts such as magnesium chloride, amountsof between about 5 and 25% have been successfully employed. In allinstances, the concentration of the catalyst is based on the weight ofthe resin solids employed.

Following the application of the resin and curing catalyst to thetextile fabric, the material is subject to drying and curing operationsto effect the properties of shrinkage control and wrinkle resistance.The drying and curing operation may be carried out in a single step orin separate steps. The temperatures at which the drying and curingoperations are effective vary widely and are infiuenced to some extentby the type of catalyst employed. Normally, the range of temperatureextends from about 180 F. to about 450 F. or even higher. Generallyspeaking, the time of the drying and/ or curing operation is inverselyproportional to the temperature employed, and of course is influenced bywhether or not separated or combined drying and curing steps areemployed.

Generally, when drying and curing is carried out in a combinedoperation, a time of from about 1 minute to about 10 minutes may beemployed at temperatures from about 450 to 250 F., respectively. Whenthe fabric has been dried preliminary to curing, curing times of theorder of 5 minutes to about A minute at a temperature of from between250 and 450 B, respectively, have been successfully employed.

In order to better illustrate the present invention, the followingexamples are given primarily by way of illustration. No specific detailsor enumerations contained therein should be construed as limitations onthe present invention except insofar as they appear in the appendedclaims. All parts and percentages contained therein are by weight unlessotherwise specifically designated.

EXAMPLE 1 Into a suitable reaction vessel there were charged 189 parts(1.5 moles) of melamine, 300 parts (9.4 moles) of methanol andapproximately 3 parts of 80% triethanolamine. After adding 495 parts (15moles) of formaldehyde as 91% paraformaldehyde at C., the reactionmixture was heated to 70 C. over approximately 30 minutes and held at 70C. for an additional two hours.

To this reaction mixture, there were added 338 parts (10.6 moles) ofmethanol, approximately 18 parts (0.18 mole) of concentrated sulfuricacid, and 100 parts (0.75 mole) of the monoethyl ether of diethyleneglycol. These charges were made while the reaction mixture was at atemperature of 30 C.

After stirring at 30 C. for minutes, the pH was adjusted to 8.9 with asodium hydroxide solution. The reaction mixture was filtered and thefiltrate (1192 parts, representing an 81% recovery, equivalent to 1.22moles of melamine) was concentrated in vacuo. The residue Weighed 770parts and contained 77.5% solids. The product also contained 12.5% freeformaldehyde equivalent to 96 parts or 3.2 moles.

Into a suitable reaction vessel, 259 parts of the above product,equivalent to 0.411 mole of melamine and containing 1.08 moles of freeformaldehyde, and 83.6 parts of a 40% solution of ethylene urea (0.389mole) were heated at C. for 15 minutes. After cooling at 30 C. thereaction mixture was filtered. The light colored vis- EXAMPLE 2 Into asuitable reaction vessel, there was charged 4070 parts (127 moles) ofmethanol, 2000 parts (15.9 moles) of melamine and 40 parts of 80%triethanolamine. At 40 C. and a pH of 9.5, there were added 5200 parts(158 moles) of formaldehyde as 91% paraformaldehyde. The reactionmixture was heated to 70 C. and held for two hours at 70 C., whereuponthe pH was 8.4. After cooling to 70 C., 4070 parts (127 moles) ofmethanol, 1050 parts (7.9 moles) of the monoethyl ether of diethyleneglycol and 195 parts (2.0 moles) of 100% sulfuric acid were added. Thereaction mixture was stirred for 1 hour at 40 C. and pH equaling 3.7,and thereafter 410 parts of 10 N sodium hydroxide solution were added toproduce a pH of 9.0.

The charge was concentrated in vacuo to a viscosity on a Gardner-Holdtscale of X at C. which is equivalent to 1200-1400 centipoises at 25 C.The pH was 7.7. After adding 2000 parts of a 60% ethylene ureasuspension (1200 parts ethylene urea or 14 moles) and 1500 parts ofwater, the charge was stirred at 60-65" C. for 0.5 hour. The charge,after cooling to 40 C. was filtered.

The product contained approximately 69.4% solids, had a pH of 8.8 and afree formaldehyde content of less than 1.8%. It was infinitely dilutablewith water and had excellent stability. The viscosity at 25 C. was 67centipoises.

EXAMPLE 3 Into a suitable reaction vessel there was charged 189 parts(1.5 moles) of melamine, 384 parts (12.0 moles) of methanol andapproximately 3 parts of 80% triethanolarnine. After adding 495 parts(15 moles) of formaldehyde as 91% paraforrnaldehyde at 40 C., thereaction mixture was heated to 70 C. over approximately minutes and heldat 70 C. for two hours.

To this reaction mixture, at approximately 40 C., there was added 384parts (12.0 moles) of methanol and 100 parts (0.75 mole) of themonoethyl ether of diethylene glycol. At C. there was added 12.8 parts(0.142 mole) of 70% nitric acid to produce a pH of 3.2. After stirringat C. for 1 hour, the pH was adjusted to 8.7 with sodium hydroxidesolution. The reaction mixture, 1580 parts, was concentrated in a vacuumof 25-26 inches of mercury to a final internal temperature of 80 C. Theresidue weighed 772 parts.

772 parts of the above product, 175 parts of a 66% solution of ethyleneurea, and 150 parts of water were stirred at 60 C. for 30 minutes. Aftercooling to 40 C. the solution was filtered. It was clear at 10 C., 12C., 25 C., 37 C. and 50 C. after four weeks.

EXAMPLE 4 Various ratios of sulfuric acid to melamine were used in theetherification step following the general procedure set forth in Example1.

These results are recorded in Table I hereinbelow.

Table I hereinabove illustrates that in order for the etherification tobe complete and for the malamine reac- 10 tion product to be clear andinfinitely dilutable, the pH of the reaction mixture duringetherification should be a value of less than 4.

EXAMPLE 5 A mixture of 768 parts (24 moles) of methanol, 378 parts (3moles) of melamine, 990 parts of formaldehyde (30 moles) as 91%paraformaldehyde and approximately 6 parts of triethanolamine wereheated at 70 C. for 2 hours. The resulting mixture had a pH of 8.2.After cooling to 35 C. there was added 36 parts (0.36 mole) ofconcentrated sulfuric acid and 768 parts (24 moles) of methanol. Thereaction mixture having a pH of 3.55 was stirred for 1 hour at 40 C. ThepH was then adjusted to 9.0 to 9.5 with a solution of caustic soda. Byconcentrating 3025 parts to an internal temperature of C. with a vacuumof 26 inches of mercury, 1329 parts of syrup having a pH of about 8.0, aviscosity of 5680 centipoises, 10.5% free formaldehyde and 92.4% solidswas obtained.

A portion (665 parts) of the above materials, equivalent to 1.5 moles ofmalamine was mixed with 189 parts of a 60% solution of ethylene urea(1.32 moles) and 176 parts of water. The mixture was stirred at 60 C.for 0.5 hour. The final product obtained by filtering at 40 F. contained72.5% solids, 1.3% free formaldehyde, a pH of 9.0 and a viscosity of 50centpoises. The solution was clear after storage at 12 C., 25 C. and 37C. for one month. Crystals of sodium sulfate appeared at- -8 C.

EXAMPLE 6 A batch of concentrated fully etherified hexamethylol melamineresin, in which methanol and a relatively small amount, 0.5 mole permole of melamine, of the monoethyl ether of diethylene glycol was usedin the etherification step, was divided into three equal portions. Eachportion was reacted with ethylene urea using the amount indicated below.

The results are indicated in Table II hereinbelow.

Table II Moles of EU per mole 1. 00 Less than 2%. 1. 12 D0. 1. 25 Do.

All were infinitely soluble in water and characterized by excellentstability.

EXAMPLE 7 In Table III hereinbelow, 7.5% of the resin solids indicatedwere applied to 80 x 80 cotton cloth, using 12% of magnesium chloride asan accelerator on the weight of the resin solids in the bath. The sotreated fabric was then dried and cured for 1.5 minutes at 350 F.

The wrinkle recovery as reported therein was measured on a Monsantowrinkle recovery tester, following the tentative method 66-56, describedon page 139 of the 1956 Technical Manual and Yearbook of the AmericanAssociation of Textile Chemists and Colorists, volume 32.

The tensile strength was measured on a Scott tensile tester according tothe A.S.T.M. standards. The tear strength was measured by the standardElmendorf test.

The yellowing index is calculated by the equation:

Yellowing index=70 1 R577 where R and R are reflectance values obtainedon a recording spectrophotometer, using a magnesium carbonate block as areference standard at the wave lengths of 455 m and 577 mg,respectively.

The strength loss due to chlorine retention was measured by thetentative test method 6952, described on page 103 of theabove-identified reference.

The washings under Wrinkle Recovery were carried out at 212 F. by theprocedure described on page 106 of the 1956 Technical Manual andYearbook of the American Association of Textile Chemists and Colorists,volume 32.

The washing under Yellowing Index was done in a Laundromat washer usinga 15-minute wash cycle at 140 F. in a solution containing 0.01% soap and0.02% available chlorine at a liquor to cloth ratio of 7 to 1. Followingbleaching, the fabrics were rinsed in water at 140 F. for three 5-minutecycles and then tumble dried at from 140 F. to 145 F. for 30 minutes.

The wash under Chlorine Retention was a process wash.

T able III *Pad bath prepared using 3% Deceresol NI (reaction product ofnonylphenol and 9 moles of ethylene oxide) on the weight of the resin asdispcrsing agent.

A B C D E Wrinkle Recovery (degrees)- Initial 146 278 258 243 258 After6 washes... 157 252 212 216 236 Grab Tensile Strength: Total W+F, lb 8251 49 54 50 CHLORINE RETENTION Initial Tensile Strength:

Before chlorine 89 53 64 64 54 After chlorine. 85 45 61 65 56 Percentloss 4 15 5 O Tensile Strength After Wash:

Before chlorine 85 53 57 62 56 After chlorine. 83 49 55 62 58 Percentloss.- 2 8 4 0 0 Yellowing Index:

Initial 1. 1 0.4 1. 4 1. 2 1.6 After 25 washes..- 0.1 1. 4 7. 5 3.1 2. 9Han std v. 51. equal v. 51. fuller fuller Table III hereinaboveillustrates, among others, two important things: that the composition ofthe present invention imparts excellent wrinkle resistance, does notresult in tensile strength loss in the fabric after chlorine bleaching(even though ethylene urea is present) and results in substantially lessdiscoloration due to chlorine retention than do mixtures of othermelamine resins and ethylene urea.

EXAMPLE 8 In Table IV, 5% resin solids from the three batches preparedaccording to Example 6 having different dimethylol ethylene urea contentwere applied to 80 X 80 cotton cloth, using 12% of magnesium chloride onthe weight of resin solids in the bath, and curing for 1.5 minutes at350 F.

The tests and washes applied to the treated fabrics were the same asthose employed in Example 7 with one exception. The washes underChlorine Retention were done by the more rigorous procedure used forwashes under Wrinkle Recovery, namely, washing at 212 F. This isequivalent to a Sanforize wash. The remaining portion of the chlorinescorch test was done as described in Example 7.

1 2 Table IV 6A 6B 6C Wrinkle Recovery:

Initial (W+1) 252 257 243 After 0 washes 223 220 225 Grab tensilestrength: Total W+F, 1b...- 59 61 G0 Elmendorf Tear Strength: Total W+F,lb. 1. 88 1. l. 73

CHLORINE RETENTION Initial Tensile Strength:

Before chlorine 58 58 60 After chl0rine 52 54 55 Percent; loss 10 7 8Tensile Strength After Was Before chlorine. 57 58 58 After chlorine.-.59 G7 55 Percent loss 0 0 5 Yellowing Index:

Ini 1.4 1.3 1.4

After 25 washes..- 2. 6 2.8 2. 6 Hand. standard equal equal Table IVillustrates the effect of varying the amount of the ethylene ureacomponent in the reaction mixture with respect to the melaminecomponent. It will be seen that even though the wash test employed forthe chlorine retention test was severe, within the limits of thisinvention, the tensile strength and yellowing index values recorded aresuperior. It should further be noted that when the ethylene urea contentexceeds the upper limit, noticeable losses in tensile strength arerecorded.

It will be noted in the above illustrative examples that triethanolamineis the alkaline catalyst normally employed during methylolation of themelamine. This is because triethanolamine is a highly satisfactory anddesirable alkaline catalyst in view of its stability, whereby it is ableto maintain a substantially uniform alkaline pH within the alkalinerange required for methylolation. While it will appear reasonablyevident that other known alkaline catalyst materials may be employed, ithas been found that when the alkaline catalyst employed duringmethylolation is an alkali metal hydroxide and particular- 1y sodiumhydroxide, and that when the acidic catalyst employed duringetherification is nitric acid, that the resulting reaction mixture issuperior, particularly with respect to its yellowing index, as well asother properties. These particular and narrower aspects of the presentinvention will be illustrated hereinafter.

EXAMPLE 9 Into a suitable reaction vessel, there were charged 4070 parts(127 moles) of methanol and 37 parts of a 30% solution of sodiumhydroxide. At a pH of 11.5 there was charged 52-00 parts (158 moles) offormaldehyde as 91% paraformaldehyde. The reaction mixture was heated to46-48" C. and at pH 10.2 there was charged 2000 'parts (15.9 moles) ofmelamine. The reaction mixture was heated to reflux (78-80 C.) for onehour, whereupon the pH was 9.0. After cooling to about 70 C., 4070 parts(127 moles) of methanol, 1050 parts (7.9 moles) of the monoethyl etherof diethylene glycol, and parts (1.71 moles) of 71% nitric acid wereadded to produce a pH of about 2. The reaction mixture was stirred forone hour at 40 C. and thereafter 182 parts of 10 N sodiumhydroxidesolution were added to produce a pH of 9.0.

The reaction mixture was concentrated in vacuo until a temperaturereached 80 C. and the distillate amounted to 1900 parts. The pH was 7.2.After adding 2800 parts of a 60% ethylene urea suspension and 1700 partsof water, the charge was stirred at 6065 C. for 0.5 hour. The pH wasadjusted to 8.2 with a 10 N solution of sodium hydroxide and the charge,after cooling to 40 C., was filtered.

The product contained approximately 69.8 solids at a pH of 8.2 and afreeformaldehyde content of about 2%. It was infinitely dilutable with Waterand characterized by 5 excellent stability. Its viscosity at 25 C, was30 poises.

13 EXAMPLE 10 The same general procedure as that employed in Example 9was followed herein, with the exception that 3000 parts of a 40%ethylene urea suspension and 700 parts of water were added during themethylolation of the ethylene urea and the charge Was stirred at 60 C.for 0.5 hour. Then 4700 parts of water were added.

The product contained approximately 51% solids.

EXAMPLE 11 In Table V hereinbelow 6% of the resin solids obtained fromthe batches prepared in accordance with Example 2, Example 9 and Example10, were applied to 80 x 80 cotton percale, using 12% magnesium chlorideas an ac- Celerator based on the weight of the resin solids in the bath.The treated fabric was then dried and cured for 2 minutes at 350 C.

The tests and washes applied to the treated fabrics were the same asthose applied in Example 7, with the following exceptions: the 160 F.and 180 F. washes under Yellowing Index were carried out by the procedure described as Test Method 14-53 on page 106 of the 1956 TechnicalManual and Yearbook of the American Association of Textile Chemists andColorists, volume 32, using temperatures of 160-180 F., respectively,with Tide, a synthetic detergent, employed in place of soap, with 0.02%of available chlorine in the wash liquor.

Table V hereinabove illustrates that when the alkaline catalyst employedduring methylolation is specifically sodium hydroxide, and the acidiccatalyst employed during alkylation is nitric acid, in the process ofthis invention (Examples 9 and 10), that a product resulting in animproved and superior yellowing index is provided. This superiorimprovement is of the order of at least 30%.

EXAMPLE 12 In Table VI below 6% of the indicated resin solids wereapplied to 80 x 80 cotton percale using 12% magnesium chloride on theweight of the resin solids in the bath. The treated fabric was thendried and cured for 2 minutes at 350 F. The tests and washes applied tothe treated fabric were the same as those employed in Example 11.

' Table VI Dimethylol ethylene urea Hexamethyl hexamethylol melamine(Solution achieved with dispersing agent) Product of Example 10 Productof Example 2 Yellowing Index:

Initial After 25 Washes at 140 C After Washes at 160 C In addition toillustrating that the resinous reaction product prepared in accordancewith the procedure of Example is superior in yellowing index after both25 Washes at 140 C. and after 5 washes at 160 C., with respect to theresinous mixture prepared in accordance with Example 2, Table VI furtherillustrates that the reaction mixture prepared in accordance withExample 10 in which the alkaline catalyst is sodium hydroxide and inwhich the acidic catalyst is nitric acid, is superior with respect tohexamethyl hexamethylol melamine and is more closely comparable toethylene urea with respect to yellowing index than anymelamine-containing blend heretofore known.

In addition to the superior yellowing index achieved by the reactionmixture of the present invention, when the above-identified alkaline andacid catalyst are employed in the process of manufacture, thisparticular resinous reaction mixture is characterized by improvedresistance to soiling, with respect to blends prepared in accordancewith Example 2. The improved resistance to soiling of this reactionmixture is more clearly illustrated when white cellulosic fabricsfinished with the resin prepared in accordance with Example 2 and theresin prepared in accordance with Example 10 are laundered in thepresence of synthetic soil. In such a laundering procedure, a cellulosicfabric treated with the former is characterized by a tendency to morereadily absorb the synthetic soil (soiling) than that finished with thelatter. This same superiority is noted to a lesser degree under actuallaundering conditions.

EXAMPLE 13 Three different melamine resins identified as follows: ResinA-a substantially fully methylated, substantially fully methylolatedmelamine, Resin Ba tris(methoxymethyl) dimethylol melamine, and ResinC-a tris (methoxymethyl) melamine, were employed in combination withdimethylol ethylene urea in three different mole ratios. These were: EUcomponent to melamine component of 0.66, 1.40 and 3.00. Only the firstof these ratios, namely 0.66, is within applicants claimed mole ratiorange.

A total of nine applications were made employing the various blends.These applications were made on x 80 bleached cotton percale so as toapply 5% resin solids based on the dry weight of the fabric, and theapplied resin was cured for 1 /2 minutes at 350 F. The catalyst was 12%of magnesium chloride based on the resin solids in the pad bath.

All applications of the above combination of resins resulted inacceptable wrinkle recovery values. However, insofar as their yellowingindices and strength loss due to chlorine retention, the compositioncontemplated by the present invention was dramatically superior, as willbe seen in Table VII hereinbelow.

In Table VII the results reported under Yellowness Index were determinedas described in Example 7 hereinabove after one wash employing oxalicacid and chlorine. In this wash the finished cloth in a 40:1 liquor tocloth ratio was washed at F. for 10 minutes in 2% of oxalic acid. It isthereafter rinsed and at the same liquor to cloth ratio is washed in .15available chloride at F. for 20 minutes. The so washed fabric is thenrinsed, dried, conditioned and tested. The strength loss due to chlorineretention was determined in accordance with the procedure referred to inExample 7 after 5 washes at 200 F.

Table VII Yellowness Index AATCC Chlorine Retention Ration After 1Oxalic Resin (EU:MEL.) Acid-Chlorine After 5 x 200 F.

Wash Washes In. 01. Percent So. So. T.S. Loss 1. 0.66 11. 6 34 29 15Resin A.-. 2. 1.40. 11.6 38 20 49 3. 3.00 9. 9 40 17 58 4. 0.66 16. 5 3827 29 Resin B 5. 1.40. 16.2 39 22 44 6. 3.00- 13. 5 39 22 44 7. 0.66-24. 0 44 10 77 Resin C- 8. 1.40 22. 4 41 11 73 9. 3.00..- 17.3 40 11 73Table VII above clearly demonstrates that application 1 of the Resin Agroup is dramatically superior, both with respect to the yellowing indexand strength loss due to chlorine retention. This application,application 1, employed a composition contemplated by this invention,while applications 29 employ compositions outside the scope of theinstant invention.

While the products prepared in accordance with copending applicationSerial No. 732,814 require the presence of a monoalkyl ether ofdiethylene glycol or a monoalkyl ether of ethylene glycol as these termsare defined hereinabove, during the etherification step in order toobtain a suitable soluble product characterized by good stability, suchmodification does not appear to be necessary insofar as the presentcomplex resinous composition is concerned. The reason for thisdifference in behavior may be that in the present invention a slightamount of polymerization has occurred, which tends to give stability tothe final product without affecting solubility. This is believed to betrue and to be supported by the fact that a physical mixture of ahexarnethyl ether of hexamethylol melamine and a dimethyl ethylene ureaare not completely soluble in each other and is characterized by poorstability.

Whether a selected glycol monoalkyl ether is employed or not, theresinous reaction product of this invention may be characterized assubstantially monomeric, meaning .that the product is essentiallymonomeric in nature and if polymer is present, the amount or extent isinsufiicient to adversely affect the solubility and stabilitycharacteristics of the product.

The resinous composition of the present invention may be employed withother textile finishing resins, either thermosetting or thermoplastic,to improve the durability of such finishes or to modify the hand orother characteristics of the finished fabric. Thus, for example, theresinous product of this invention may be employed with ureaformaldehyderesins, various other cyclic ureas, as for example, 1,2-propyleneurea-formaldehyde resins, 1,3-propylene urea-formaldehyde resins,guanamine-formaldehyde resins and their alkylated derivatives. Among thethermoplastic resins which may be mentioned are homopolymers andcopolymers of lower alkylacrylates, such as methyl acrylates, ethylacrylates, methyl methacrylates, butyl methacrylates or copolymers ofthese or their equivalents with styrenes, including ring and chainsubstituted styrenes, acrylonitrile, polyvinyl chloride, and the like.In addition, the resinous mixture of this invention may be employed withsofteners, stiffeners, lubricants, dicyanamide and other conventionaltreating bath components, where compatible.

We claim:

1. A process for preparing an infinitely water-soluble, substantiallyfully etherified, substantially fully methylolated melamine-ethyleneurea-formaldehyde textile finishing resin characterized by excellentstability and suitable for use in imparting shrinkage control andwrinkle recovery to cellulose containing textile material, with minimumdeleterious effects due to chlorine retention, which comprises reactingrelative mole ratios of one mole of melamine and an excess offormaldehyde in an amount'between 8.0 and moles of formaldehyde asparaformaldehyde at a temperature between C. and 80 C. and at a pHbetween 7 and 11 in the presence of at least 6 moles of methanol until aclear solution is formed and reaction is complete, adding sufiicientadditional methanol to the reaction mixture to make a total of at least10 moles of said methanol in the reaction mixture, adjusting the pH ofthe reaction mixture to a value below 4, stirring said mixture at atemperature of between 15 and 60 C. until a complete solution isobtained, adjusting the pH of the solution to between 8 and 10, addingfrom between 0.6 and 1.2 moles of ethylene urea, reacting said ethyleneurea and said excess formaldehyde to form dimethylol ethylene urea at atemperature between 30 C. and C. until reaction is complete.

2. A process according to claim 1 in which from between 0.25 and 1.0moles of a monoalkyl ether of diethylene glycol, wherein the alkyl groupcontains 1 to 4 carbon atoms, is added to the reaction mixture prior tothe adjustment of the pH thereof to below 4.

3. A process according to claim 2 in which the monoalkyl ether ofdiethylene glycol is the monoethyl ether of diethylene glycol.

4. A process for preparing an infinitely water-soluble, substantiallyfully etherified, substantially fully methylolated melamine-ethyleneurea-formaldehyde textile finishing resin characterized by excellentstability and suitable for use in imparting shrinkage control andwrinkle recovery to cellulose containing textile material, with minimumdeleterious effects due to chlorine retention, which comprises reactingrelative mole ratios of one mole of melamine and an excess offormaldehyde in an amount between 8.0 and 20 moles of formaldehyde asparaformaldehyde at a temperature between 30 C. and 80 C. and at a pHmaintained between 7 and 11 with sodium hydroxide in the presence of atleast 6 moles of methanol until a clear solution is formed and reactionis complete, adding sufiicient additional methanol to the reactionmixture to make a total of at least 10 moles of said methanol in thereaction mixture, adjusting the pH of the reaction mixture to a valuebelow 4 with nitric acid, stirring said mixture at a temperature ofbetween 15 and 60 C. until a complete solution is obtained, adjustingthe pH of the solution to between 8 and 10, adding from between 0.6 and1.2 moles of ethylene urea, reacting said ethylene urea and said excessformaldehyde to form dimethylol ethylene urea at a temperature between30 C. and 80 C. until reaction is complete.

5. An infinitely water-soluble, stable textile finishing resincomposition containing on a relative mole basis 1 mole of asubstantially fully etherified, substantially fully methylolatedmelamine, said etherified methylol melamine having at least 5.8 methylolgroups and at least 5.6 etherifying groups, and from between.0.6 and 0.8mole of dimethylol ethylene urea, said etherifying groups beingprincipally methyl with up to about 2.5 of said groups being selectedfrom the group consisting of alkoxyethoxyethyl wherein alkoxy contains 1to 4 carbon atoms and alkoxyethyl, wherein alkoxy contains 1 to 3 carbonatoms.

10/59 Scott 260.69

MURRAY TILLMAN, Primary Examiner.

LEON J. BERCOVITZ, Examiner.

1. A PROCESS FOR PREPARING AN INFINITELY WATER-SOLUBLE, SUBSTANTIALLYFULLY ETHERIFIED, SUBSTANTIALLY FULLY METHYLOLATED MELAMINE-ETHYLENEUREA-FORMALDEHYDE TEXTILE FINISHING RESIN CHARACTERIZED BY EXCELLENTSTABILITY AND SUITABLE FOR USE IN IMPARTING SHRINKAGE CONTROL ANDWRINKLE RECOVERY TO CELLULOSE CONTAINING TEXTILE MATERIAL, WITH MINIMUMDELETERIOUS EFFECTS DUE TO CHLORINE RETENTION, WHICH COMPRISES REACTINGRELATIVE MOLE RATIOS OF ONE MOLE OF MELAMINE AND AN EXCESS OFFORMALDEHYDE IN AN AMOUNT BETWEEN 8.0 AND 20 MOLES OF FORMALEHYDE ASPARAFORMALDEHYDE AT A TEMPERATURE BETWEEN 30*C. AND 80*C. AND AT A PHBETWEEN 7 AND 11 IN THE PRESENCE OF AT LEAST 6 MOLES OF METHANOL UNTIL ACLEAR SOLUTION IS FORMED AND REACTION IS COMPLETE, ADDING SUFFICIENTADDITIONAL METHANOL TO THE REACTION MIXTURE TO MAKE A TOTAL OF AT LEAST10 MOLES OF SAID METHANOL IN THE REACTION MIXTURE, ADJUSTING THE PH OFTHE REACTION MIXTURE TO A VALUE BEFOW 4, STIRRING SAID MIXTURE AT ATEMPERATURE OF BETWEEN 15 ADN 60*C. UNTIL A COMPLETE SOLUTION ISOBTAINED, ADJUSTING THE PH OF THE SOLUTION TOBETWEEN 8 AND 10, ADDINGFROM BETWEEN 0.6 AND 1.2 MOLES OF ETHYLENE UREA, REACTING SAID ETHYLENEUREA AND SAID EXCESS FORMALDEHYDE TO FORM DIMETHYLOL ETHYLENE UREA AT ATEMPERATURE BETWEEN 30*C. AND 80*C. UNTIL REACTION IS COMPLETE.